Question

(a) Cu is oxidized; Sn is reduced (b) anode: \(\mathrm{Cu}(s) \longrightarrow \mathrm{Cu}^{2+}(a q)+2 e^{-}\) cathode: \(\mathrm{Sn}^{2+}(a q q)+2 \mathrm{e}^{-} \longrightarrow \mathrm{St}(s)\)

Short answer

Cu is oxidized and the reaction is: \( \mathrm{Cu}(s) \rightarrow \mathrm{Cu}^{2+}(aq) + 2e^{-} \). Sn is reduced and the reaction is: \( \mathrm{Sn}^{2+}(aq) + 2e^{-} \rightarrow \mathrm{Sn}(s) \).

Step-by-step solution

Identify Oxidation and Reduction

Determine which elements are oxidized and reduced. Copper (Cu) is oxidized as it loses electrons, forming Cu²⁺ ions: \( \mathrm{Cu}(s) \rightarrow \mathrm{Cu}^{2+}(aq) + 2e^{-} \). Tin (Sn²⁺) is reduced as it gains electrons to form solid tin: \( \mathrm{Sn}^{2+}(aq) + 2e^{-} \rightarrow \mathrm{Sn}(s) \).

Write the Anode Reaction

The anode is where oxidation occurs. For copper: \( \mathrm{Cu}(s) \rightarrow \mathrm{Cu}^{2+}(aq) + 2e^{-} \). This equation shows copper losing two electrons and forming copper ions.

Write the Cathode Reaction

The cathode is where reduction occurs. For tin: \( \mathrm{Sn}^{2+}(aq) + 2e^{-} \rightarrow \mathrm{Sn}(s) \). This equation shows tin ions gaining two electrons to form solid tin.

Key concepts

Electrochemistry

Electrochemistry is the branch of chemistry that deals with the relationship between electricity and chemical reactions. In simple terms, it studies how chemical energy is converted into electrical energy and vice versa. For instance, batteries and electroplating are practical applications of electrochemistry.

Electrochemical cells, or galvanic cells, are devices that convert chemical energy into electrical energy. These cells consist of two different electrodes, usually made of different metals, immersed in an electrolyte solution. When a chemical reaction occurs at the electrodes, electrons are transferred between them through an external circuit, producing an electric current.

Key components of an electrochemical cell include:

• Anode (where oxidation occurs)
• Cathode (where reduction occurs)
• Electrolyte (a medium that allows ion movement)

Understanding these components is crucial for grasping how electrochemistry works.

Redox Reactions

Redox reactions, short for reduction-oxidation reactions, are chemical processes where electrons are transferred between substances. These reactions are fundamental in both chemistry and biology and play a vital role in energy production and various industrial processes.

In a redox reaction, oxidation is the loss of electrons, while reduction is the gain of electrons. The substance that gives away electrons is oxidized, and the one that gains electrons is reduced. To remember this easily, you can use the acronym OIL RIG (Oxidation Is Loss, Reduction Is Gain).

Let's look at the provided exercise example:

• Copper (Cu) is oxidized: \(\text{Cu}(s) \rightarrow \text{Cu}^{2+}(aq) + 2e^{-}\)
• Tin (Sn^{2+}) is reduced: \(\text{Sn}^{2+}(aq) + 2e^{-} \rightarrow \text{Sn}(s)\)

Here, copper loses electrons (undergoing oxidation), and tin gains electrons (undergoing reduction). Understanding these processes helps in identifying which substances are oxidized and reduced in a given reaction.

Anode and Cathode

In any electrochemical cell, the anode and the cathode are essential components that drive the redox reactions.

The anode is the electrode where oxidation occurs. In the provided exercise, copper (Cu) acts as the anode: \(\text{Cu}(s) \rightarrow \text{Cu}^{2+}(aq) + 2e^{-}\). This equation indicates that copper atoms lose electrons, forming copper ions that dissolve into the electrolyte solution.

The cathode is the electrode where reduction occurs. In the exercise, tin (Sn^{2+}) serves as the cathode: \(\text{Sn}^{2+}(aq) + 2e^{-} \rightarrow \text{Sn}(s)\). Tin ions in the solution gain electrons and form solid tin.

To summarize:

• The anode is where oxidation (electron loss) takes place. For copper: \( \text{Cu}(s) \rightarrow \text{Cu}^{2+}(aq) + 2e^{-} \).
• The cathode is where reduction (electron gain) occurs. For tin: \( \text{Sn}^{2+}(aq) + 2e^{-} \rightarrow \text{Sn}(s) \).

Knowing the roles of anode and cathode helps in understanding how electrochemical cells work and how electrons flow through the external circuit, generating electricity.